U.S. patent application number 11/584550 was filed with the patent office on 2007-04-26 for information device.
This patent application is currently assigned to Renesas Technology Corporation. Invention is credited to Tomoko Ando, Takahiko Arakawa, Makoto Hatakenaka, Motoki Higashida, Masayuki Koyama, Kikuo Muramatsu, Hideo Nagano.
Application Number | 20070091122 11/584550 |
Document ID | / |
Family ID | 37984882 |
Filed Date | 2007-04-26 |
United States Patent
Application |
20070091122 |
Kind Code |
A1 |
Nagano; Hideo ; et
al. |
April 26, 2007 |
Information device
Abstract
An information device includes a main processing circuit for
executing signal processing related to a main function in the
information device, a main microcomputer for controlling the main
processing circuit, a receiver circuit for interfacing with the
outside of the information device, and an interface microcomputer
for controlling the receiver circuit, the interface microcomputer
being provided separately from the main microcomputer.
Inventors: |
Nagano; Hideo; (Tokyo,
JP) ; Muramatsu; Kikuo; (Tokyo, JP) ; Koyama;
Masayuki; (Tokyo, JP) ; Ando; Tomoko; (Tokyo,
JP) ; Higashida; Motoki; (Tokyo, JP) ;
Arakawa; Takahiko; (Tokyo, JP) ; Hatakenaka;
Makoto; (Tokyo, JP) |
Correspondence
Address: |
BUCHANAN, INGERSOLL & ROONEY PC
POST OFFICE BOX 1404
ALEXANDRIA
VA
22313-1404
US
|
Assignee: |
Renesas Technology
Corporation
Tokyo
JP
|
Family ID: |
37984882 |
Appl. No.: |
11/584550 |
Filed: |
October 23, 2006 |
Current U.S.
Class: |
345/629 ;
348/E5.009; 386/E5.07 |
Current CPC
Class: |
H04N 5/04 20130101; H04N
5/85 20130101; H04N 5/775 20130101; G09G 5/006 20130101 |
Class at
Publication: |
345/629 |
International
Class: |
G09G 5/00 20060101
G09G005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 26, 2005 |
JP |
2005-310939 |
Claims
1. An information device comprising: a main processing circuit for
executing signal processing related to a main function in said
information device; a first microcomputer for controlling said main
processing circuit; an interface circuit for interfacing with the
outside of said information device; and a second microcomputer for
controlling said interface circuit, said second microcomputer being
provided separately from said first microcomputer.
2. The information device according to claim 1, wherein said
interface circuit and said second microcomputer are subjected to a
single-chip process separately from said main processing circuit
and said first microcomputer.
3. The information device according to claim 1, wherein said
interface circuit and said second microcomputer are connected to
each other by using a parallel interface.
4. The information device according to claim 2, further comprising
a memory for storing firmware for controlling said interface
circuit, said memory being formed on a semiconductor chip different
from another semiconductor chip on which said second microcomputer
is formed, wherein said second microcomputer downloads said
firmware from said memory to execute said firmware.
5. The information device according to claim 2, wherein said
interface circuit receives an externally inputted video signal and
an externally inputted audio signal corresponding to said video
signal to output said video signal and said audio signal in
parallel, said information device further comprising a lip-sync
circuit for adjusting the timing between said video signal and said
audio signal outputted in parallel from said interface circuit,
said lip-sync circuit being subjected to the single-chip process
together with said interface circuit and said second
microcomputer.
6. The information device according to claim 2, wherein said
interface circuit includes a receiver circuit for receiving an
external signal to output said external signal, and a transmitter
circuit for outputting a signal outputted from said receiver
circuit to the outside of said information device.
7. The information device according to claim 2, wherein said second
microcomputer has the function of communicating with said first
microcomputer.
8. The information device according to claim 2, wherein said
interface circuit includes first and second interface circuits for
interfacing with the outside of said information device under
different specifications, said information device further
comprising a selection circuit for activating one of said first and
second interface circuits in accordance with the specification of
an external signal, said selection circuit being subjected to the
single-chip process together with said interface circuit and said
second microcomputer.
9. The information device according to claim 2, further comprising:
a plurality of input ports for receiving respective external
signals; and a switch circuit for selecting one of the external
signals inputted to said plurality of input ports to output a
selected signal to said interface circuit, said switch circuit
being subjected to the single-chip process together with said
interface circuit and said second microcomputer.
10. The information device according to claim 2, wherein said
interface circuit receives an encrypted signal inputted from the
outside of said information device, decrypts said encrypted signal,
and outputs the decrypted signal, said information device further
comprising a watermarking circuit for embedding a watermark into a
signal outputted from said interface circuit to output the
resultant signal, said watermarking circuit being subjected to the
single-chip process together with said interface circuit and said
second microcomputer.
11. The information device according to claim 1, wherein said
interface circuit is an interface circuit conforming to HDMI
(High-Definition Multimedia Interface).
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an information device
including a main processing circuit, an interface circuit, and a
microcomputer.
[0003] 2. Description of the Background Art
[0004] Conventionally, a variety of standards have been proposed
for an interface between information devices. For example, HDMI
(High-Definition Multimedia Interface) is known as a high-speed
serial interface. Devices which adopt the HDMI as an interface are
disclosed in Japanese Patent Application Laid-Open No. 2005-189587
and Japanese Patent Application Laid-Open No. 2004-248080. The HDMI
is well known as a digital interface which transmits high-quality
audio/video (A/V) content data between a source device such as a
DVD (Digital Versatile Disk) device, an STB (Set-Top Box) and the
like and a sink device such as a plasma display device, a digital
television set and the like. The HDMI is characterized by the
capability of transmitting encrypted information, the capability of
transmitting a video signal and an audio signal at the same time,
the capability of transmitting uncompressed data in real time, a
transmission rate of 3.5 Gbps and a wide transmission band, and the
like.
[0005] In the conventional information device, an interface circuit
for interfacing with the outside based on the HDMI or other
standards and a main processing circuit for performing signal
processing related to a main function in the information device
have been controlled by the same microcomputer. In a display device
such as a plasma display device as an example, a receiver circuit
for receiving and outputting a video signal, an audio signal and
the like transmitted from a source device such as a DVD device by
using a predetermined interface and a signal processing circuit for
performing a format conversion process and like related to video
display and audio output upon the video and audio signals outputted
from the receiver circuit are controlled by the same microcomputer.
Thus, the single microcomputer is required to execute firmware for
controlling the interface circuit and firmware for controlling the
main processing circuit, and therefore has the problem of bearing a
heavy load during real-time processing. It is also necessary to
develop the firmware for controlling the interface circuit and the
firmware for controlling the main processing circuit in the same
environment. This provides an increased development load, and
becomes one of the causes of the slowdown of the development.
Similar problems arise in the source device such as the DVD
device.
SUMMARY OF THE INVENTION
[0006] It is therefore an object of the present invention to
provide a technique for an information device including a main
processing circuit, an interface circuit and a microcomputer, which
is capable of speeding up the development of the information device
while reducing a processing load on the microcomputer.
[0007] According to the present invention, an information device
includes: a main processing circuit for executing signal processing
related to a main function in the information device; a first
microcomputer for controlling the main processing circuit; an
interface circuit for interfacing with the outside of the
information device; and a second microcomputer for controlling the
interface circuit, the second microcomputer being provided
separately from the first microcomputer.
[0008] The information device includes the second microcomputer for
controlling the interface circuit separately from the first
microcomputer for controlling the main processing circuit. Thus,
firmware for controlling the interface circuit can be executed by
the microcomputer different from the microcomputer which executes
firmware for controlling the main processing circuit. This reduces
a processing load on one microcomputer.
[0009] Additionally, the interface circuit and the second
microcomputer may be implemented in the form of an IP (Intellectual
Property) core. This facilitates the formation of the interface
circuit and the second microcomputer together with the main
processing circuit and the first microcomputer on a single
semiconductor chip, and reduces the labor of the verification of
circuit operation at the time of the integration of the interface
circuit and the second microcomputer together with the main
processing circuit and the first microcomputer.
[0010] These and other objects, features, aspects and advantages of
the present invention will become more apparent from the following
detailed description of the present invention when taken in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a block diagram showing the construction of an
information device according to a first preferred embodiment of the
present invention;
[0012] FIG. 2 is a block diagram showing the construction of a
modification of the information device according to the first
preferred embodiment of the present invention;
[0013] FIG. 3 is a block diagram showing the construction of an
information device according to a second preferred embodiment of
the present invention;
[0014] FIG. 4 is a block diagram showing the construction of an
information device according to a third preferred embodiment of the
present invention;
[0015] FIG. 5 is a block diagram showing the construction of an
information device according to a fourth preferred embodiment of
the present invention;
[0016] FIG. 6 is a block diagram showing the construction of an
information device according to a fifth preferred embodiment of the
present invention;
[0017] FIG. 7 is a block diagram showing the construction of an
information device according to a sixth preferred embodiment of the
present invention;
[0018] FIG. 8 is a block diagram showing the construction of an
information device according to a seventh preferred embodiment of
the present invention;
[0019] FIG. 9 is a block diagram showing the construction of an
information device according to an eighth preferred embodiment of
the present invention; and
[0020] FIG. 10 is a block diagram showing the construction of an
information device including all of the functions of the
information devices according to the second to eighth preferred
embodiments of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
First Preferred Embodiment
[0021] FIG. 1 is a block diagram showing the construction of an
information device 100 according to a first preferred embodiment of
the present invention. The information device 100 according to the
first preferred embodiment is a display device such as, for
example, a plasma display device and a liquid crystal display
device. For example, HDMI is used as an interface between the
information device 100 and the outside thereof.
[0022] As shown in FIG. 1, the information device 100 according to
the first preferred embodiment includes a receiver circuit 1 for
interfacing with the outside of the information device 100, an
interface microcomputer 2 for controlling the receiver circuit 1, a
main processing circuit 3 for performing signal processing related
to a main function in the information device 100, and a main
microcomputer 4 for controlling the main processing circuit 3.
[0023] The receiver circuit 1 is an interface circuit which, based
on the HDMI standard, receives an HDMI input signal INS inputted
from another information device (referred to hereinafter as an
external device) outside the information device 100. The receiver
circuit 1 includes an HDMI analog core 11, an HDMI logic core 12,
and an 12C (Inter-Integrated Circuit) interface section 13.
[0024] The HDMI analog core 11 is a high-speed SERDES
(serializer/de-serializer) circuit, and converts the HDMI input
signal INS which is a serial signal into a parallel signal to
output the parallel signal to the HDMI logic core 12. The I2C
interface section 13 exchanges a control signal CNT with the
external device, based on the DDC (Display Data Channel) standard.
The I2C interface section 13 sends and receives the control signal
CNT by using an I2C interface.
[0025] The HDMI logic core 12 is controlled by the interface
microcomputer 2. The HDMI logic core 12 exchanges the control
signal CNT with the external device through the I2C interface
section 13 to thereby perform an authentication process, and
thereafter decrypts the HDMI input signal INS which is encrypted.
The HDMI input signal INS is encrypted using a digital encryption
scheme known as an HDCP (High-bandwidth Digital Content Protection)
system. The HDMI logic core 12 extracts a video signal VS and an
audio signal AS from the decrypted HDMI input signal INS, decodes
the video signal VS and the audio signal AS into a predetermined
format, and generates a clock signal CLKV synchronized with the
decoded video signal VS and a clock signal CLKA synchronized with
the decoded audio signal AS. The HDMI logic core 12 also extracts a
synchronization signal SS for video display from the decrypted HDMI
input signal INS, and decodes the synchronization signal SS into a
predetermined format. Thereafter, the HDMI logic core 12 outputs
the video signal VS, the audio signal AS, the clock signals CLKA
and CLKV, and the synchronization signal SS in parallel to the main
processing circuit 3.
[0026] The interface microcomputer 2 includes an MPU (Micro
Processing Unit) core 21 for controlling the HDMI logic core 12, a
program ROM (Read Only Memory) 22 for storing therein firmware FWI
for controlling the HDMI logic core 12, a work RAM (Random Access
Memory) 23 which the MPU core 21 uses as a storage area while the
MPU core 21 is in operation, an interrupt controller 24 for
controlling an interrupt process in the MPU core 21, and a
watchdog-timer 25. The components 21 to 25 are connected to each
other through an MPU bus 26.
[0027] The program ROM 22 is a ROM in which information can be
electrically rewritten, such as a flash ROM. The firmware FWI in
the program ROM 22 is rewritable.
[0028] The MPU core 21 is connected to the HDMI logic core 12 by
using the I2C interface. The MPU core 21 reads the firmware FWI
from the program ROM 22 to execute the firmware FWI, thereby
controlling the operation of the HDMI logic core 12. For example,
the MPU core 21 initializes the HDMI logic core 12 or controls the
HDMI logic core 12 to extract a predetermined packet signal from
the HDMI input signal INS. This packet signal contains format
information about the video signal VS, and the MPU core 21 outputs
the packet signal to another circuit not shown in the information
device 100. The watchdog timer 25 resets the MPU core 21 in
cooperation with the interrupt controller 24 when the MPU core 21
runs away or when power to the information device 100 is
instantaneously interrupted.
[0029] The main processing circuit 3 includes an audio signal
processing circuit 31, and a video signal processing circuit 32.
The information device 100 according to the first preferred
embodiment is a display device which provides an audio output based
on an externally inputted audio signal and produces a video display
based on an externally inputted video signal. Therefore, the main
functions of the information device 100 are the video display based
on an external video signal and the audio output based on an
external audio signal, and the main processing circuit 3 according
to the first preferred embodiment performs various signal
processing related to these functions.
[0030] The audio signal processing circuit 31 and the video signal
processing circuit 32 operate in synchronism with the clock signal
CLKA and the clock signal CLKV, respectively, which are outputted
from the receiver circuit 1. The audio signal processing circuit 31
performs a filter process and the like on the audio signal AS
outputted from the receiver circuit 1, converts the audio signal AS
which is a digital signal into an analog signal, and outputs the
analog signal to a loudspeaker not shown. The loudspeaker converts
the audio signal inputted thereto into a sound to output the sound
to the outside. The video signal processing circuit 32, on the
other hand, converts the video signal VS outputted from the
receiver circuit 1 into an RGB format or a YGbGr format. Also, the
video signal processing circuit 32 performs a filter process on the
video signal VS, and outputs the resultant signal together with the
synchronization signal SS to a display section not shown. The
display section produces a video display based on the video signal
VS and the synchronization signal SS inputted thereto. Thus, at the
same time that the video display is produced, the audio output
corresponding to the video display is provided, whereby the
information device 100 functions as, for example, a television
set.
[0031] The main microcomputer 4 is similar in internal construction
to the interface microcomputer 2, and stores therein firmware FWM
for controlling the main processing circuit 3. The main
microcomputer 4 executes the firmware FWM to thereby control the
main processing circuit 3.
[0032] In the information device 100 according to the first
preferred embodiment, the receiver circuit 1 and the interface
microcomputer 2 are subjected to a "single-chip process" separately
from the main processing circuit 3 and the main microcomputer 4.
The term "single-chip process" used herein shall mean both the
process of forming a plurality of circuits on a single
semiconductor chip, irrespective of how the plurality of circuits
are packaged, and the process of housing a plurality of circuits
into a single package although the plurality of circuits are formed
on different semiconductor chips. Therefore, the term "single chip"
means both a single semiconductor chip, and a device including one
or more semiconductor chips housed in a single package. The main
processing circuit 3 and the main microcomputer 4 may or need not
be subjected to the "single-chip process."
[0033] As an example according to the first preferred embodiment,
the receiver circuit 1 and the interface microcomputer 2 are formed
on a single semiconductor chip 5 different from another
semiconductor chip 50 on which the main processing circuit 3 and
the main microcomputer 4 are formed. Thus, the receiver circuit 1
and the interface microcomputer 2 are subjected to the single-chip
process separately from the main processing circuit 3 and the main
microcomputer 4. The semiconductor chip 5 is housed and molded in a
single package not shown together with or separately from the
semiconductor chip 50 on which the main processing circuit 3 and
the main microcomputer 4 are formed.
[0034] The main processing circuit 3 and the main microcomputer 4
are formed on the single semiconductor chip 50 according to the
first preferred embodiment. However, the main processing circuit 3
and the main microcomputer 4 may be formed on different
semiconductor chips.
[0035] Alternatively, as shown in FIG. 2, the receiver circuit 1 is
formed on a single semiconductor chip 5a whereas the interface
microcomputer 2 is formed on another semiconductor chip 5b. The
receiver circuit 1 and the interface microcomputer 2 are housed in
a package 15 different from another package 150 in which the main
processing circuit 3 and the main microcomputer 4 are housed. Thus,
the receiver circuit 1 and the interface microcomputer 2 may be
subjected to the single-chip process separately from the main
processing circuit 3 and the main microcomputer 4.
[0036] In the instance shown in FIG. 2, the main processing circuit
3 and the main microcomputer 4 are shown as housed in the single
package 150. However, the main processing circuit 3 and the main
microcomputer 4, when formed on different semiconductor chips, may
be housed in different packages whereas the receiver circuit 1 and
the interface microcomputer 2 be housed in another package
different from the above-mentioned packages.
[0037] As described above, the information device 100 according to
the first preferred embodiment includes the interface microcomputer
2 for controlling the receiver circuit 1 separately from the main
microcomputer 4 for controlling the main processing circuit 3.
Thus, the firmware FWI for controlling the receiver circuit 1 can
be executed by the microcomputer different from the microcomputer
which executes the firmware FWM for controlling the main processing
circuit 3. This reduces a processing load on one microcomputer.
[0038] The firmware FWI for controlling the receiver circuit 1 and
the firmware FWM for controlling the main processing circuit 3,
which are executed by the different microcomputers, may be
developed in different environments. This allows the speedup of the
development of the information device 100.
[0039] Additionally, the receiver circuit 1 and the interface
microcomputer 2 may be implemented in the form of an IP
(Intellectual Property) core. This facilitates the formation of the
receiver circuit 1 and interface microcomputer 2 together with the
main processing circuit 3 and the main microcomputer 4 on a single
semiconductor chip, and reduces the labor of the verification of
circuit operation at the time of the integration of the receiver
circuit 1 and the interface microcomputer 2 together with the main
processing circuit 3 and the main microcomputer 4.
[0040] According to the first preferred embodiment, the receiver
circuit 1 and the interface microcomputer 2 are subjected to the
single-chip process separately from the main processing circuit 3
and the main microcomputer 4. This improves the confidentiality of
the interface between the receiver circuit 1 and the interface
microcomputer 2 to increase security, and also improves the
flexibility of the arrangement of the receiver circuit 1 and the
interface microcomputer 2.
[0041] The receiver circuit 1 and the interface microcomputer 2
according to the first preferred embodiment are connected to each
other by using the I2C interface which is a serial interface, but
may be connected to each other by using a parallel interface. This
reduces circuit size and power consumption.
Second Preferred Embodiment
[0042] FIG. 3 is a block diagram showing the construction of an
information device 200 according to a second preferred embodiment
of the present invention. As shown in FIG. 3, the information
device 200 according to the second preferred embodiment includes an
interface microcomputer 20 in place of the interface microcomputer
2 provided in the information device 100 of the first preferred
embodiment described above, and further includes a ROM 6.
[0043] The interface microcomputer 20 includes the MPU core 21, the
work RAM 23, the interrupt controller 24 and the watchdog timer 25
mentioned above, and further includes a program RAM 27, an external
ROM interface section 28 and a ROM 29. These components 21, 23 to
25, and 27 to 29 are connected to each other through the MPU bus
26. The interface microcomputer 20 and the receiver circuit 1 are
formed on the same semiconductor chip 5, and are subjected to the
single-chip process separately from the main processing circuit 3
and the main microcomputer 4, as in the first preferred
embodiment.
[0044] The ROM 6 is a ROM in which information can be electrically
rewritten, such as a flash ROM. The ROM 6 stores therein the
firmware FWI for the interface microcomputer 20 to control the
receiver circuit 1. The ROM 6 is formed on a single semiconductor
chip 60 different from the semiconductor chip 5 on which the
receiver circuit 1 and the interface microcomputer 20 are formed.
Only the ROM 6 is formed on the semiconductor chip 60. The ROM 6 is
connected to the external ROM interface section 28 of the interface
microcomputer 20.
[0045] The ROM 29 in the interface microcomputer 20 is a ROM in
which information cannot be electrically rewritten, such as a mask
ROM. The ROM 29 previously stores a downloader program DLP therein.
The MPU core 21 reads the downloader program DLP from the ROM 29 to
execute the downloader program DLP, thereby reading the firmware
FWI from the ROM 6 through the external ROM interface section 28
and writing the firmware FWI into the program RAM 27. Then, the MPU
core 21 reads the firmware FWI from the program RAM 27 to execute
the firmware FWI, thereby controlling the receiver circuit 1. The
remaining structure of the information device 200 according to the
second preferred embodiment is similar to that of the information
device 100 according to the first preferred embodiment, and will
not be described.
[0046] In the information device 200 according to the second
preferred embodiment as described above, the interface
microcomputer 20 downloads the firmware FWI from the ROM 6 formed
on the semiconductor chip 60 different from the semiconductor chip
5 on which the interface microcomputer 20 is formed, to execute the
firmware FWI. This eliminates the need to form a memory for
previously storing the firmware FWI such as a flash ROM on the
semiconductor chip 5 on which the interface microcomputer 20 is
formed. In general, the incorporation of a memory into a
microcomputer makes the manufacturing process thereof complicated
to increase manufacturing costs. Therefore, the formation of the
interface microcomputer 20 and the ROM 6 which stores the firmware
FWI on the different semiconductor chips simplifies the
manufacturing process of the interface microcomputer 20 to reduce
the manufacturing costs.
[0047] Although the manufacturing process of the interface
microcomputer 20 becomes complicated, the ROM 6 may be incorporated
into the interface microcomputer 20 and be formed on the
semiconductor chip 5.
Third Preferred Embodiment
[0048] FIG. 4 is a block diagram showing the construction of an
information device 300 according to a third preferred embodiment of
the present invention. As shown in FIG. 4, the information device
300 according to the third preferred embodiment principally
includes a lip-sync circuit 7 for adjusting the timing between the
audio signal AS and the video signal VS in addition to the
components of the information device 100 of the first preferred
embodiment mentioned above.
[0049] The main microcomputer 4 according to the third preferred
embodiment measures a time lag between the time at which the audio
signal AS is outputted from the audio signal processing circuit 31
and the time at which the video signal VS corresponding to the
audio signal AS is outputted from the video signal processing
circuit 32, and generates a delay amount instruction signal DS
based on the time lag to output the delay amount instruction signal
DS to the lip-sync circuit 7. Based on the delay amount instruction
signal DS inputted thereto, the lip-sync circuit 7 delays at least
one of the audio signal AS and the video signal VS which are
outputted in parallel from the receiver circuit 1 to output the
processed audio and video signals AS and VS to the audio signal
processing circuit 31 and the video signal processing circuit 32,
respectively. When delaying the video signal VS, the lip-sync
circuit 7 accordingly delays the synchronization signal SS, and
then outputs the synchronization signal SS. This corrects the time
lag between the audio signal AS and the video signal VS at outputs
of the main processing circuit 3 to ensure the synchronization
between the audio signal AS and the video signal VS. Consequently,
the time lag between the video display and the corresponding audio
output is suppressed. It should be noted that the clock signals
CLKA and CLKV outputted from the receiver circuit 1 do not pass
through the lip-sync circuit 7 but are directly inputted to the
audio signal processing circuit 31 and video signal processing
circuit 32, respectively.
[0050] The lip-sync circuit 7 is subjected to the single-chip
process together with the receiver circuit 1 and the interface
microcomputer 2. As an example according to the third preferred
embodiment, the lip-sync circuit 7 is formed on the single
semiconductor chip 5 together with the receiver circuit 1 and the
interface microcomputer 2, whereby the lip-sync circuit 7 is
subjected to the single-chip process together with the receiver
circuit 1 and the interface microcomputer 2. The remaining
structure of the information device 300 according to the third
preferred embodiment is similar to that of the information device
100 according to the first preferred embodiment, and will not be
described.
[0051] In the information device 300 according to the third
preferred embodiment as described above, the lip-sync circuit 7 for
adjusting the timing between the audio signal AS and the
corresponding video signal VS which are outputted in parallel from
the receiver circuit 1 is subjected to the single-chip process
together with the receiver circuit 1 and the interface
microcomputer 2. Thus, the time lag between the audio signal AS and
the video signal VS is corrected by using a single-chip device.
This consequently suppresses the time lag between the video display
and the corresponding audio output.
Fourth Preferred Embodiment
[0052] FIG. 5 is a block diagram showing the construction of an
information device 400 according to a fourth preferred embodiment
of the present invention. As shown in FIG. 5, the information
device 400 according to the fourth preferred embodiment principally
includes a transmitter circuit 8 in addition to the components of
the information device 100 of the first preferred embodiment
described above.
[0053] The transmitter circuit 8 is controlled by the interface
microcomputer 2 to operate. The transmitter circuit 8 encodes the
audio signal AS, the video signal VS and the synchronization signal
SS which are outputted in parallel from the receiver circuit 1 into
a predetermined format, and thereafter rearranges the audio signal
AS, the video signal VS and the synchronization signal SS which are
inputted thereto in parallel into serial chronological order. Then,
the transmitter circuit 8 encrypts the resultant signal by using
the HDCP system, converts the encrypted signal into a serial
signal, and outputs the serial signal as an HDMI output signal OUTS
to the external device. Thus, the HDMI input signal INS inputted to
the information device 400 is relayed by the receiver circuit 1 and
the transmitter circuit 8, and is then outputted as the HDMI output
signal OUTS to the outside of the information device 400.
[0054] The transmitter circuit 8 is subjected to the single-chip
process together with the receiver circuit 1 and the interface
microcomputer 2. As an example according to the fourth preferred
embodiment, the transmitter circuit 8 is formed on the single
semiconductor chip 5 together with the receiver circuit 1 and the
interface microcomputer 2, whereby the transmitter circuit 8 is
subjected to the single-chip process together with the receiver
circuit 1 and the interface microcomputer 2. The remaining
structure of the information device 400 according to the fourth
preferred embodiment is similar to that of the information device
100 according to the first preferred embodiment, and will not be
described.
[0055] In the information device 400 according to the fourth
preferred embodiment as described above, the receiver circuit 1
which receives and outputs the externally inputted signal and the
transmitter circuit 8 which outputs the signal outputted from the
receiver circuit 1 to the outside are subjected to the single-chip
process. Thus, a repeater function for relaying an external signal
to output the external signal is implemented by a single-chip
device.
Fifth Preferred Embodiment
[0056] FIG. 6 is a block diagram showing the construction of an
information device 500 according to a fifth preferred embodiment of
the present invention. As shown in FIG. 6, the information device
500 according to the fifth preferred embodiment is such that the
function of communicating with the main microcomputer 4 is
implemented in the interface microcomputer 2 of the information
device 100 of the first preferred embodiment mentioned above. The
interface microcomputer 2 and the main microcomputer 4 are
connected to each other by using, for example, the I2C interface,
to be able to exchange signals with each other. The remaining
structure of the information device 500 according to the fifth
preferred embodiment is similar to that of the information device
100 according to the first preferred embodiment, and will not be
described.
[0057] In the information device 500 according to the fifth
preferred embodiment as described above, the interface
microcomputer 2 has the function of communicating with the main
microcomputer 4. This enables the interface microcomputer 2 to be
controlled from the main microcomputer 4 in accordance with the
operating conditions of the main processing circuit 3. For example,
the main microcomputer 4 can reset the interface microcomputer 2 to
initialize the operation of the interface microcomputer 2 when a
cable for connection between the information device 500 and the
external device is accidentally disconnected so that neither the
audio signal AS nor the video signal VS is inputted to the main
processing circuit 3 or when the audio signal AS and the video
signal VS are not normally inputted from the receiver circuit 1 to
the main processing circuit 3.
[0058] The function of communicating with the main microcomputer 4
may be implemented in the interface microcomputer 2 of the
information device 300 of the third preferred embodiment mentioned
above. This enables the interface microcomputer 2 to receive the
delay amount instruction signal DS outputted from the main
microcomputer 4 and to output the delay amount instruction signal
DS to the lip-sync circuit 7.
Sixth Preferred Embodiment
[0059] FIG. 7 is a block diagram showing the construction of an
information device 600 according to a sixth preferred embodiment of
the present invention. As shown in FIG. 7, the information device
600 according to the sixth preferred embodiment principally
includes a receiver circuit 10 and a receiver selection circuit 9
in addition to the components of the information device 100 of the
first preferred embodiment described above.
[0060] The receiver circuit 10 has a circuit configuration similar
to that of the receiver circuit 1 according to the first preferred
embodiment, and interfaces with the outside of the information
device 600. Like the receiver circuit 1, the receiver circuit 10 is
controlled by the interface microcomputer 2 to receive the HDMI
input signal INS from the external device and to exchange the
control signal CNT with the external device. However, the receiver
circuit 10 conforms to a different version of the HDMI standard
than that of the receiver circuit 1. For example, the receiver
circuit 10 interfaces with the external device in conformity with
the HDMI version 1.2, whereas the receiver circuit 1 interfaces
with the external device in conformity with the HDMI version 1.1. A
bus connection is established between an output terminal of the
receiver circuit 10 and an output terminal of the receiver circuit
1.
[0061] The control signal CNT according to the sixth preferred
embodiment contains information about which HDMI version the HDMI
input signal INS outputted from the external device conforms to.
The receiver selection circuit 9 refers to the information
contained in the control signal CNT to recognize the HDMI version
to which the HDMI input signal INS conforms, thereby outputting a
chip select signal CS to the receiver circuits 1 and 10, based on
the recognized version. This activates one of the receiver circuits
1 and 10 which conforms to the version of the HDMI input signal
INS. The interface microcomputer 2 receives activation information
from the receiver selection circuit 9 to recognize the activated
receiver circuit based on the activation information, thereby
controlling the operation of the activated receiver circuit.
[0062] Under the control of the interface microcomputer 2, the
receiver circuit activated in this manner by the receiver selection
circuit 9 performs the serial-to-parallel conversion process, the
decryption process and the like on the HDMI input signal INS to
extract the audio signal AS, the video signal VS and the
synchronization signal SS from the HDMI input signal INS, thereby
outputting these signals and the clock signals CLKA and CLKV in
parallel to the main processing circuit 3. On the other hand, the
output terminal of the receiver circuit which is not activated by
the receiver selection circuit 9 is placed in a high impedance
state. Thus, the audio signal AS, the video signal VS and the like
from the activated receiver circuit are normally inputted to the
main processing circuit 3.
[0063] The receiver selection circuit 9 and the receiver circuit 10
are subjected to the single-chip process together with the receiver
circuit 1 and the interface microcomputer 2. As an example
according to the sixth preferred embodiment, the receiver selection
circuit 9 and the receiver circuit 10 are formed on the single
semiconductor chip 5 together with the receiver circuit 1 and the
interface microcomputer 2, whereby the receiver selection circuit 9
and the receiver circuit 10 are subjected to the single-chip
process together with the receiver circuit 1 and the interface
microcomputer 2. The remaining structure of the information device
600 according to the sixth preferred embodiment is similar to that
of the information device 100 according to the first preferred
embodiment, and will not be described.
[0064] The information device 600 according to the sixth preferred
embodiment as described above includes the receiver circuits 1 and
10 which interface with the external device under different
specifications. One of the receiver circuits 1 and 10 is activated
by the receiver selection circuit 9 in accordance with the
specifications of the HDMI input signal INS provided from the
outside. The receiver selection circuit 9 and the receiver circuit
10 are subjected to the single-chip process together with the
receiver circuit 1 and the interface microcomputer 2. Thus, a
single-chip device can receive a plurality of external signals
different in specifications from each other.
Seventh Preferred Embodiment
[0065] FIG. 8 is a block diagram showing the construction of an
information device 700 according to a seventh preferred embodiment
of the present invention. As shown in FIG. 8, the information
device 700 according to the seventh preferred embodiment
principally includes a plurality of input ports IN1 to IN3 and an
analog switch circuit 70 in addition to the components of the
information device 100 of the first preferred embodiment described
above.
[0066] The analog switch circuit 70 is controlled by the main
microcomputer 4 to select one of a plurality of HDMI input signals
INS1 to INS3 inputted to the plurality of input ports IN1 to IN3
respectively, thereby outputting the selected signal as the HDMI
input signal INS to the receiver circuit 1.
[0067] The information device 700 according to the seventh
preferred embodiment is constructed to enable a user to enter
information indicating which one of the plurality of input ports
IN1 to IN3 receives the HDMI input signal to be processed. The
information entered by the user is inputted to the main
microcomputer 4. Then, the main microcomputer 4 controls the analog
switch circuit 70 based on the information inputted thereto. Thus,
the information device 700 processes the HDMI input signal inputted
to the port specified by the user to display an image transmitted
by the HDMI input signal and to output a sound transmitted by the
HDMI input signal.
[0068] The analog switch circuit 70 is subjected to the single-chip
process together with the receiver circuit 1 and the interface
microcomputer 2. As an example according to the seventh preferred
embodiment, the analog switch circuit 70 is formed on the single
semiconductor chip 5 together with the receiver circuit 1 and the
interface microcomputer 2, whereby the analog switch circuit 70 is
subjected to the single-chip process together with the receiver
circuit 1 and the interface microcomputer 2. The remaining
structure of the information device 700 according to the seventh
preferred embodiment is similar to that of the information device
100 according to the first preferred embodiment, and will not be
described.
[0069] In the information device 700 according to the seventh
preferred embodiment as described above, the analog switch circuit
70 for selecting one of the plurality of HDMI input signals INS1 to
INS3 to output the selected HDMI input signal to the receiver
circuit 1 is subjected to the single-chip process together with the
receiver circuit 1 and the interface microcomputer 2. Thus, a
single-chip device can process the signals inputted to the
plurality of input ports IN1 to IN3. Additionally, because the
single receiver circuit 1 can process the signals inputted to the
plurality of input ports IN1 to IN3, the seventh preferred
embodiment can construct the information device having the
plurality of input ports while preventing the significant increase
in chip size and suppressing the increase in cost.
Eighth Preferred Embodiment
[0070] FIG. 9 is a block diagram showing the construction of an
information device 800 according to an eighth preferred embodiment
of the present invention. As shown in FIG. 9, the information
device 800 according to the eighth preferred embodiment principally
includes a watermarking circuit 80 in addition to the components of
the information device 100 of the first preferred embodiment
described above.
[0071] The watermarking circuit 80 embeds a watermark (a digital
watermark or an electronic watermark) into each of the audio signal
AS and the video signal VS outputted from the receiver circuit 1 to
output the audio signal AS and the video signal VS to the main
processing circuit 3. The audio signal processing circuit 31 of the
main processing circuit 3 extracts the watermark from the audio
signal AS inputted thereto, and then processes the audio signal AS
as mentioned above. Similarly, the video signal processing circuit
32 extracts the watermark from the video signal VS, and then
processes the video signal VS as mentioned above. The clock signals
CLKA and CLKV and the synchronization signal SS are inputted from
the receiver circuit 1 directly to the main processing circuit
3.
[0072] The watermarking circuit 80 is subjected to the single-chip
process together with the receiver circuit 1 and the interface
microcomputer 2. As an example according to the eighth preferred
embodiment, the watermarking circuit 80 is formed on the single
semiconductor chip 5 together with the receiver circuit 1 and the
interface microcomputer 2, whereby the watermarking circuit 80 is
subjected to the single-chip process together with the receiver
circuit 1 and the interface microcomputer 2. The remaining
structure of the information device 800 according to the eighth
preferred embodiment is similar to that of the information device
100 according to the first preferred embodiment, and will not be
described.
[0073] In the information devices according to the first to seventh
preferred embodiments mentioned above, the uncoded audio and video
signals AS and VS which are subjected to the decryption are
inputted from the receiver circuit 1 to the main processing circuit
3. Because information about the image and sound transmitted from
the external device is easily acquired in the path between the
receiver circuit 1 and the main processing circuit 3, it is
desirable to augment security.
[0074] In the information device 800 according to the eighth
preferred embodiment, the watermark is embedded into the audio
signal AS and the video signal VS which are subjected to the
decryption by the watermarking circuit 80 subjected to the
single-chip process together with the receiver circuit 1 and the
interface microcomputer 2, and the audio signal AS and the video
signal VS are thereafter inputted to the main processing circuit 3.
This makes the leakage of the information about the image and the
sound more difficult, to increase the security.
[0075] The information devices according to the first to eighth
preferred embodiments adopt the HDMI as the interface with the
outside, but may adopt other standards than the HDMI standard.
[0076] As shown in FIG. 10, an information device 900 having all of
the functions of the information devices according to the second to
eighth preferred embodiments mentioned above may be provided by
adding the lip-sync circuit 7, the transmitter circuit 8, the
receiver selection circuit 9, the receiver circuit 10, the
plurality of input ports IN1 to IN3, the analog switch circuit 70
and the watermarking circuit 80 mentioned above to the information
device 200 according to the second preferred embodiment mentioned
above and by implementing the function of communicating with the
main microcomputer 4 in the interface microcomputer 2.
[0077] While the invention has been described in detail, the
foregoing description is in all aspects illustrative and not
restrictive. It is understood that numerous other modifications and
variations can be devised without departing from the scope of the
invention.
* * * * *